In general, this invention relates to a fluid valve with wide temperature range and, more particularly, to a fluid valve with wide temperature range of a type particularly suited for metering or pressure regulating fuel in an aircraft gas turbine engine fuel system wherein the fuel may be either liquid or gaseous and may vary rapidly from a cryogenic temperature to a high temperature.
During the current energy crisis many drastic measures have been suggested to conserve our precious fuel reserves. One of these measures involves the curtailment of scheduled airline flights in order to save petroleum which can otherwise be refined into home heating oil or gasoline. It has been recently suggested that other fuels such as liquified natural gas (methane) and liquid hydrogen might be used interchangeably to power aircraft gas turbine engines, particularly those of the supersonic variety. Such a change in aircraft fuels would have the immediate effect of making available large quantities of petroleum for other purposes. In addition, a liquid hydrogen fuel system may have broader application such as to recoverable space vehicle, for use in a space shuttle program.
Before liquified natural gas and liquid hydrogen can be used as fuel for an aircraft gas turbine engine, suitable fuel systems will have to be developed which can function properly under severe temperature differentials. Such temperature differentials may vary as much as from -400.degree.F to + 1,050.degree.F or higher and will impose severe expansion problems on vital fuel system components such as metering and pressure regulating valves, where variable area orifices must remain operable in all temperature ranges. Severe changes in the sizes of conventional metering valve components due to variations in temperature may cause binding or seizing of the valve components thus being unacceptable for safe engine operation.
Therefore, it is a primary object of this invention to provide either a metering or pressure regulating valve suitable for use in a temperature variable fuel system in a gas turbine engine.
It is a further object of this invention to provide a metering valve wherein the variable metering orifices remain operable despite rapid temperature variations in the regulated fluid of from -400.degree.F to + 1,050.degree.F.
It is also an object of this invention to provide a metering valve or pressurizing valve wherein the regulated fluid may be natural gas or hydrogen in either the liquid or gaseous state.